The Organic Light Emitting Diodes (OLED) display device possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, short response time, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as the most potential display device.
The OLED display element is a self-emitting type display device, and generally comprises a pixel electrode and a common electrode respectively employed as being the anode and the cathode, and an organic light emitting layer positioned between the pixel electrode and the common electrode. As the proper voltages are applied to the anode and the cathode, the organic light emitting layer emits light. The organic light emitting layer comprises a Hole Injection Layer positioned on the anode, a Hole Transporting Layer positioned on the Hole Injection Layer, a light emitting layer positioned on the Hole Transporting Layer, an Electron Transport Layer positioned on the light emitting layer and an Electron Injection Layer positioned on the Electron Transport Layer. The lighting principle is that under certain voltage driving, the Electron and the Hole are respectively injected into the Electron Injection Layer and Hole Electron Injection Layer from the cathode and the anode. The Electron and the Hole respectively migrate from the Electron Transporting Layer and Hole Transporting Layer to the Emitting layer and bump into each other in the Emitting layer to form an exciton to excite the emitting molecule. The latter can illuminate after the radiative relaxation.
With the requirement of the people for the portable display apparatus gets bigger and bigger, the flexible display technology has become one of the display technologies which have extreme competitive advantage. The one biggest advantage of the flexible display technology is to possess the foldability, which can occupy smaller space under the premise of providing a larger display region. Please refer to FIG. 1 and FIG. 2, which are diagrams of unfolding structure and folding structure of the three levels foldable display device according to prior art. The foldable display device comprises a first display region 100′, a first folding region 200′, a second display region 300′, a second folding region 400′ and a third display region 500′, which are continuously aligned from left to right along a horizontal direction. The foldable display device can be folded at the first folding region 200′ and the second folding region 400′ to achieve the foldable function. In prior art, the drive circuit of the foldable and flexible display device is designed to be the dual side drive. With the length increase of the foldable display device, the power consumption of the drive circuit will greatly increase. For the OLED pixel circuit with compensation design, the drive signal needs to drive a plurality of Thin film transistors (TFT), and the power consumption of the drive circuit will be larger. In general, after the foldable display device is folded, the display is only performed on the first display region 100′ on the top, and the second and the third display region 300′, 500′ do not require showing images because of being folded and shaded. In prior art, the data signal is not inputted so that the other display regions do not perform display for saving the electrical power. However, after being folded, the scan drive signal still drive the TFTs in the second and the third display region 300′, 500′ and cause the electrical power waste to shorten the mobile apparatus usage duration and influence the user experience. Meanwhile, the loading of the drive circuit is larger, the voltage drop happens to the TFT gates of the first display region 100′ away from the drive signal, and the display quality is descended.